Of the list Cyan, if you had replaced Cyan with the true old guy of FFVI (Strago) then I would go with Cid Highwind, if you replaced Cid with the true old guy of FFVII (RedXIII) then Steiner from FFIX if you had included him, but if Steiner is replaced with Quina since he/she is older but doesn't fully qualify as a "guy", then RedXIII and if we're not counting RedXIII since he's 17 in dog years or whatever then Galuf.